Jump to: Metadata Field Operators │ List of Common Field Operators │ List of Collection Codes │ Searching MODs Metadata Show Search Query OperatorsBecause queries can be very complex and can use several different operators, there needs to be a way to evaluate expressions unambiguously. This is done through the use of operator precedence, which is a way of specifying which operators and expressions are evaluated first, second, and so on. In the list below, the precedence of the operators is from first to last.
The sections that follow will show you how to use a variety of characters and operators to narrow your search. SpacesA space is used to separate words or operators in a search query. In a simple query where operators are not used, spaces between words are treated as an implied "and" so that the search results will contain documents containing all of the words that have been entered. Note: In certain cases, the search engine will automatically assume that two terms separated by a single space should be treated as a single phrase to increase the accuracy of results. This primarily occurs with proper names. For complex queries using operators, the following should be noted:
Example To search for only those documents that contain both the words Bill and Clinton, you can enter Bill Clinton into the Search Box and click the Search button. The search engine will look for both words in the document and return those documents where both words can be found anywhere in the document. Quotation MarksQuotation marks tell the search engine to return documents if and only if they contain the exact phrase or string of words between quotes. Examples
Boolean OperatorsA Boolean search is a search that uses the logical (i.e., Boolean) operators (AND, OR, NOT, -) in addition to the keywords.
Note: Boolean operators are not case sensitive. For example, entering and or AND will return the same results. Examples
Proximity OperatorsProximity Operators allow you to specify searches where one word is near, next to, or in the vicinity of another word. The three proximity operators defined are:
Examples
Note: Because a proximity expression is trying to find words (or phrases with quotes) that are located within a specified proximity of each other, using Boolean operators or multiple words without quotes in a proximity expression will result in a search query error. One way to make sure that you do not get search query errors is to always use parentheses around the proximity expression when creating search queries that use proximity operators. Examples of proximity expressions using quotes:
ParenthesesParentheses are used to group words and expressions so that the result of evaluating the expression between the parentheses can be used as part of a more complex query. The use of parentheses is recommended to isolate expressions in your query from other expressions, especially when creating complex queries using proximity operators and field operators. Examples
Number of HitsThe Number of hits "+" operator can be used to specify that documents with more hits on a particular word be given preference over documents with hits on other words. Examples
Wild CardsWild cards can be used as substitutions for one or more characters in a search term
Examples
Metadata Field OperatorsField operators are operators that represent metadata fields. Using field operators tells the search engine to retrieve documents where the value of the metadata field is equal to the value given in the field operator expression. Searches with field operators are useful when you know the values of descriptive data (metadata) such as titles, sponsors, and dates. Range is used to specify the set of all values a query should return.
When using field operators, you must observe the following rules:
Examples
The table below lists commonly used field operators that apply to all or most of the collections. Lists of collection-specific metadata field operators are available under the What's Available section. Common Field Operators for Most CollectionsMetadata Field Display NameField OperatorExampleCollectioncollection:collection:chrgGovernment Authorgovernmentauthor:governmentauthor:housePublication Datepublishdate:publishdate:2006-09-30SuDoc Class Numbersudocclass:sudocclass:"y 4.c 73/8:"Ingestion Dateingestdate:ingestdate:2008-12-29Publisherpublisher:publisher:"u.s. government printing office"Branchbranch:branch:legislativeTitletitle:title:(railroad safety)Congress Numbercongress:congress:109Congress Membermember:member:mcconnellPresidentpresident:president:clintonCitationcitation:citation:"Public Law 105-264"Reference Citationrefcitation:refcitation:"Public Law 105-264"Electronic Location (URL)url:url:"http://www.gpo.gov/fdsys/pkg/BILLS-111hr1071IH/pdf/BILLS-111hr1071IH.pd…;Package IDpackageid:packageid:FR-2009-03-31Granule IDgranuleid:granuleid:E9-7073 Collection CodesCollection CodeCollection Name GPO Additional Government Publications GOVPUB Bulk Government Publications CZIC Coastal Zone Information Center CFR Code of Federal Regulations COMPS Statute Compilations CPD Compilation of Presidential Documents BILLS Congressional Bills CCAL Congressional Calendar CPRT Congressional Committee Prints CDIR Congressional Directory CDOC Congressional Documents CREC Congressional Record CRECB Congressional Record (Bound Edition) CRI Congressional Record Index CRPT Congressional Reports ECONI Economic Indicators ERP Economic Reports of the Presidents ERIC Educations Reports from ERIC FR Federal Register GAOREPORTS GAO Reports and Comptroller General Decisions HOB History of Bills HJOURNAL House Journal HMAN House Manual LSA List of CFR Sections Affected PAI Privacy Act Issuances PLAW Public and Private Laws PPP Public Papers of the Presidents of the United States SMAN Senate Manual USCODE United States Code USCOURTS United States Courts Opinions GOVMAN United States Government Manual STATUTES United States Statutes at Large BUDGET President's Budget DOI Department of Interior Inspector General Reports ERP Economic Report of the President (1995) HJOURNAL Journal of the House of Representatives Searching MODS MetadataMODS is a metadata standard that includes information about a digital object. It stands for Metadata Object Description Schema and the standard is maintained by the Library of Congress. What is the most useful Boolean operator?The most popular Boolean commands are AND, OR, and NOT. Other commands include parentheses, truncation, and phrases.
Which Boolean operators is used to narrow a search?Use AND in a search to: narrow your results. tell the database that ALL search terms must be present in the resulting records.
Which Boolean operator can narrow or limit the number of search results?The more search terms you add with AND, the more you will restrict your results, and the fewer results you will get. AND is most useful when you have two or more keywords and want to make sure all are included in each of your search results.
What is the Boolean operator of the Internet?Boolean operators are the words "AND", "OR" and "NOT". When used in library databases (typed between your keywords) they can make each search more precise - and save you time!
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